Observational cosmology. Cosmic evolution of galaxies and AGN and feedback mechanisms. Physics of extragalactic radio sources and AGN. Large-scale structure and the cosmic evolution of galaxy clusters. Next-generation radio telescopes and their role in constraining cosmological parameters, dark energy and hot and cold dark matter.

The Daily Mail reports that Dr Sivia is thought to have been arrested at the scene on suspicion of murder. Dr Sivia is a fellow at St John's College.